Area Code Atlas

NPA 724 split from 412

Area code 724 was created in 1998 as a geographic split from 412, taking over most of the territory outside of Pittsburgh. The split was chosen over an overlay due to resistance to ten-digit dialing at the time.

NPA 724 split from 412

On February 1, 1998, area code 724 was created from a split of 412, assigning nearly all of the 412 territory outside Allegheny County to the new code. This change made 412 an enclave for the city of Pittsburgh, while 724 served the surrounding suburbs and southwestern Pennsylvania.

NPA 878 to Overlay NPAs 412 and 724 (Pennsylvania)

Permissive 10-digit dialing begins for 412 and 724

Permissive 10-digit dialing began on July 17, 2000, for calls within and between the 412 and 724 area codes in preparation for the 878 overlay. Callers could use either seven or ten digits during this transition period.

Ten-digit dialing becomes mandatory in southwestern Pennsylvania

In 2001, ten-digit dialing became mandatory across southwestern Pennsylvania due to the implementation of the 878 overlay for both 412 and 724. This change affected all customers in the region.

Rationing in NPAs 412, 724, and 878 (Pennsylvania)

Mandatory 10-digit dialing for 412 and 724

Mandatory 10-digit dialing was implemented on July 12, 2001, for all calls within and between the 412 and 724 area codes, coinciding with the overlay of area code 878. Seven-digit dialing was discontinued.

NPA 878 overlay implemented for 412 and 724

Area code 878 was activated on August 17, 2001, as an all-services overlay for both 412 and 724 in southwestern Pennsylvania. This overlay required mandatory ten-digit dialing throughout the region and was implemented after both 412 and 724 faced number exhaustion.

Mandatory ten-digit dialing begins in 412, 724, and 878 simultaneously

Ten-digit dialing became mandatory in the 412, 724, and 878 numbering plan areas on August 17, 2001, coinciding with the activation of the 878 overlay to accommodate growing demand for telephone numbers in southwestern Pennsylvania.

Announcement to begin issuing 878 numbers in 724 territory

The Pennsylvania Public Utility Commission announced on February 15, 2013, that it would begin assigning 878 numbers in the 724 area due to near exhaustion of available 724 numbers. This marked the first practical use of 878 numbers more than a decade after the overlay's activation.

Announcement to start issuing 878 numbers in 724 territory

The Pennsylvania Public Utility Commission announced it would start issuing 878 numbers in the 724 territory within the next year due to near exhaustion of 724 numbers.

First 878 numbers issued in 724 territory in April 2013

The first telephone numbers using area code 878 were issued in the 724 territory in April 2013 after exhaustion of available central office codes in 724. Numbers in the 412 territory were assigned later, marking the beginning of active 878 assignments in the overlay area.

First 878 numbers assigned in 724 territory

The first telephone numbers with area code 878 were assigned in the 724 territory in April 2013, nearly 12 years after the overlay was activated.

First telephone numbers assigned for area code 878 in 724 region

In 2015, telephone numbers were first assigned for area code 878 in the 724 region, completing the activation of the overlay across both 412 and 724.